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(No Model.)

W. A. JACKSON & J. 0. CHAMBERS.

PROUESSOF NEUTRALIZING INDUCTION.

No. 322,728. Patented July 21,1885.

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NITED STATES PATENT OFFICE.

WILLIAM A. JAoKSoN AND JOSEPHUS o. CHAMBERS, OF DETROIT, MIOEL, ASSIGNORS TO GEORGE H. LOTHROP, TRUSTEE, OF SAME rLAoE.

PROCESS OF NEUTRALIZING INDUCTION.

SPECIFICATION forming part of Letters Patent No, 322,728, dated July 21, 1885.

Application filed February 4, 1885. (No model.)

To all whom, it may concern:

Be it known that we, WILLIAM A. JACK- SON and J OSEPHUS G. CHAMBERS, of Detroit, in the county of Wayne and State of Michigan, have invented a new and useful Improvement in Process of Neutralizing Induction Disturbances in Telephone-Circuits, of which the following is a specification.

Our invention is a process of neutralizing the disturbing currents generated in a telephonecircuit by induction from external wires, &c.; and it consists in opposing said disturbing currents byinduced charges generated by said disturbing currents in one or more insulated bodies, which are good conductors, and are capable of being electrically charged by induction, which will hereinafter be called inductive bodies, for brevity.

The disturbing currents caused in a telephone-circuit by induction from external obj ectssuch as other wires, the earth, &c.are generally of higher tension than the normal telephonic currents, and have therefore a much greater tendency to create induced charges in inductive bodies adjacent to the line traversed by such currents thanhas the telephonic cur rent. lVe utilize this by placing one or more inductive bodies in electrical proximity to the telephone-circuit, but insulated therefrom, so that an inductive influence will be mutually exerted by said telephonecircuit and the said inductive body upon each other.

In several applications heretofore filed by us for Letters Patent, among which are Nos. 133,378, filed May 31, 1884,140,647, 140,648, and 147 ,240, we have shown and described several modes of arranging the inductive bodies and circuit, and in the first of said applications described the process which forms the subject of this application. As the several arrangements of mechanism therein shown form the subject-matter of said applications, we do not here claim any particular arrangement of mechanism.

In the drawings which we have chosen to herein illustrate some of the arrangements of mechanism which may be used to practice our process, Figure 1 is a vertical longitudinal Section in which A represents abundle of wires, either copper or iron, preferably Soft iron, insulated from the line and preferably, though not necessarily, insulated from each other. L

represents the line-wire of the circuit wound in a helix around wires A, and grounded in the usual manner through the telephones at its respective ends. We prefer to place that part of the line which is coiled around the wires A close to the telephone, as it there yields the maximum result.

Fig. 2 is a vertical longitudinal section through an induction-coil, in which P is the primary to be connected with a battery and transmitter in the'usual manner B, the core; N, a spool or bobbin, of wood or iron, in which latter case it may be made integralwith B; S, the secondary, and G G, wires of copper or iron, like A, interposed between and insulated from the layers of the secondary.

Fig. 3 is a similar view to Fig. 2, showing the line-wire L, a core or bobbin, B, of either iron or wood,and the insulated wires 00, being a modification of the arrangement shown in Fig. 2, designed for use with a telephone in which the ordinary induction-coil is to be retained, and simply inserted in the circuit, as explained with reference to Fig. 1.

Fig.4 is an elevation of a partly-made coil, and Fig. 5 a vertical section of a finished coil, which embodies the most satisfactory arrangement devised by us. B represents a core, made of iron, on which are cast or screwed or forged four projecting pole-pieces, b b b b. D represents an insulated wire, either copper or iron, preferably soft iron, wound around the body of the core, and having its ends free, and preferably disconnected, as shown in Fig. 5. P represents the primary, wound over the core B and wireD, and connected with a battery and transmitter in the usual manner, as shown at Rand T, Fig. 5. S represents the secondary wound over the primary and connected with the line and ground wires, as shown in Fig. 5. L represents that end of the line-wire which runs to earth through the receiving-telephone. H represents a helix of insulated wire wound over the secondary, and with its ends preferably disconnected, as shown in Fig. 5. W represents strips of wood at each end of the core, to make a finish to the ends of the coil. This coil is a complete coil, and is designed for use in the transmitter-boxes in place of the ordinary induction-coils usually placed therein. This arrangement is illustrated in Fig. 6, wherein '1 T represent two transmitters at diflerent stations, K K represent two complete induction-coils like those shown in Figs. 2 and 5, L represents the line-wire connecting the two stations, and M M represent binding-posts on the transmitters, to which the line-wire is attached.

It is evident that any piece of iron interposed between and insulated from B and the primary will be an electrical equivalent for D.

It will be noticed that in each arrangement of mechanism we place one or more inductive bodies, (represented by A, G, B b, and H,) in electrical proximity to, but insulated from, the circuit or line wire L; and, as these inductive bodies are usually placed in the transmitier-box or near the telephone, they are little exposed to any electrical excitement except that which is caused by electrical currents flowing in the circuit.

WVhen a telephone-circuit is put to use in talking, the receivingtelephone is affected by the normal telephonic current from the sending-station, and also by currents generated in the circuit by induction from other wires and external objects, which cause in the receivingtelephone rattling cracking sounds, often so loud as to drown the sound produced by the telephonic current. When a telphone-circuit through which these two classes of currents are flowing is brought into electrical proximity to one or more insulated inductive bodies, the said currents tend to cause induced charges in the inductive body or bodies, which, by their inductive reaction on the adjacent convolutions of the circuit, oppose and neutralize to a very great extent the disturbing currents of high tension due to atmospheric and other influences outside of the main line; but by reason of their comparatively low tension this reaction has little effect upon the normal telephonic currents, which flow on into the receiving-telephone.

What we claim as our invention, and desire to secure by Letters Patent, is

1. The herein-described method or process of neutralizing induction disturbances in a telephone-circuit, consisting in opposing the disturbing currents by induced charges generated by said disturbing currents and reacting upon said disturbing currents.

2. Ihe herein-described method or process of neutralizing disturbing currents in a telephonecircuit by establishing an equilibrium between said disturbing currents and electrical charges of opposite polarity inductively generated by said disturbing-currents.

WILLIAM A. JACKSON.

J OSEPHUS C. CHAMBERS.

Witnesses? SUMNER OoLLINs, OYRUs E. LOTHROP. 

